The proposed research concerns the movement of materials across the intestine of the parasitic roundworm Ascaris suum. It involves determinations of: 1) the transport of ions, sugars and amino acids across the intestine; 2) the ability of the basement membrane to function as a diffusion barrier; and 3) the mode of action of the anthelmintic drug, mebendazole, upon the transport of non-electrolytes by the intestine. Pilot studies with a modified Ussing chamber and voltage clamp device show that a potential of 10-50 mV develops across the in vitro intestine and a rapid change in the Isc occurs upon addition of glucose to the test system. The polarity of the potential is the reverse of that observed with the vertebrate intestine. Work is proposed to determine: 1) the ion species that is responsible for the development of the potential; 2) the forward and back flux of sugars and amino acids; 3) the quantitative relationship between flux rates of sugars and amino acids and observed changes in the Isc and 4) the effect of various inhibitors upon flux rates and Isc. It is possible to isolate the basement membrane of the intestine from the epithelial cells. Preliminary work has been done and further work is proposed to determine the permeability of the membrane to a series of hydrophilic, non-ionic molecules of graded molecular size. The results will be evaluated for information concerning the membranes' potential to serve as a diffusion barrier. Mebendazole appears to inhibit the movement of nutrients across the intestine of Ascaris. The Km of sugar uptake and the Ki of mebendazole will be determined. The data will be examined to see if the inhibition is competitive or noncompetitive.